1. Field of the Invention
The present invention relates to an automatic ice maker of the open-cell type.
2. Discussion of the Prior Art
Illustrated in FIG. 8 is a conventional automatic ice maker of the open-cell type which includes a box type housing 1 composed of a pair of side walls 1a connected to each other by means of rear and front walls 1b and 1c, a water storage tank 2 mounted to a bottom portion of housing 1, a sprinkler 3 provided with a plurality of nozzles 3a and mounted on the water storage tank 2, an ice making dish plate 4a mounted within an ice making chamber 4 formed in an upper portion of housing 1, a plurality of cup-shaped ice making cell casings 4b coupled with the corresponding holes of the dish plate 4a and welded in place, and an inclined ice chute 6 in the form of a lattice located under the ice making cell casings 4b and mounted to the side walls 1a of housing 1. The ice making cell casings 4b are arranged to open downward. In addition, a shutter 7 is suspended from the front wall 1c of housing 1 and is normally closed by weight. During the defrost cycle in operation of the ice maker, fresh water is supplied to the dish plate 4a by means of a water supply conduit 8. When the defrost cycle in operation of the ice maker finishes, the water is discharged from a drain passage (not shown).
A cooling pipe 5 fixedly mounted on the ice making cell casings 4b as shown in FIGS. 9(a) and 9(b) is connected to a refrigerant conduit 10 to be supplied with cooled refrigerant from a freezing circuit including a compressor 11, a condenser 12 cooled by a cooling fan 13, a dehydrator 14 and an expansion valve 15. In the freezing circuit, a hot-gas valve 16 is provided in parallel with the condenser 14, dehydrator 14 and expansion valve 15. When the freezing circuit is activated in a closed condition of the hot-gas valve 16, the ice making chamber 4 is cooled by the refrigerant supplied from the freezing circuit. When the hot-gas valve 16 is opened in a closed condition of expansion valve 15, the refrigerant is compressed by the compressor 11 and supplied as a hot-gas to the cooling pipe 5.
Ice making water W in water tank 2 is supplied into the sprinkler 3 and spouted upward from the nozzles 3a of sprinkler 3. The water is spouted across openings of the ice chute 6 into each interior of ice making cell casings 4b cooled by the refrigerant and frozen in the ice making cell casings 4b, and a remainder of the water is returned into the water tank 2. Ice cubes formed in the ice making cells 4b are enlarged in the course of lapse of a time. When the ice making cell casings 4b are filled with the ice cubes, the water for defrost is supplied to the dish plate 4a, and the hot-gas is supplied to the cooling pipe 5 to release the ice cubes from the ice making cell casings 4b. The ice cubes are received by the ice chute 6 and slip on the ice chute to open the shutter 7. Thus, the ice cubes are delivered into an ice storage cabinet (not shown) through the shutter 7.
In the ice maker, as shown in FIGS. 9(a) and 9(b), the cooling pipe 5 is secured in contact with the ice making cell casings 4b and is partly separated from the ice making cell casings at each space therebetween. Accordingly, at an ice making cycle in operation, heat transfer of the refrigerant is effected only at a portion of the cooling pipe 5 in contact with the ice making cell casings 4b, while the cooling pipe 5 does not effect heat transfer of the refrigerant at a portion separated from the ice making cell casings 4b. This results in a decrease of heat exchange efficiency of the cooling pipe 5, causing a decrease of ice making performance of the ice maker.
It is, therefore, a primary object of the present invention to provide an automatic ice maker of the open-cell type the cooling performance of which is enhanced in a simple construction.
According to the present invention, the object is accomplished by providing an automatic ice maker of the open-cell type which includes a box-type housing, a plurality of spaced ice making cell casings arranged on a horizontal plane in an upper portion of the housing and opened downward, a cooling pipe mounted on the cell casings to be supplied with refrigerant from a freezing circuit and a sprinkler mounted within a bottom portion of the housing and placed under the cell casings to spout ice making water into the respective cell casings, wherein a base plate is mounted within the upper portion of the housing to form an ice making chamber, and wherein the ice making cell casings are secured to a bottom surface of the base plate, while the cooling pipe is mounted on the base plate along positions located above the cell casings and welded to an upper surface of the base plate.
In a practical embodiment of the present invention, the ice making cell casings each are in the form of a cylindrical body welded at one end thereof to the bottom surface of the base plate. Alternatively, the ice making cell casings each are in the form of a cup-shaped casing welded at its bottom to the bottom surface of the base plate by braze welding.
According to an aspect of the present invention, the ice making cell casings each are in the form of a cylindrical body formed at one end thereof with a plurality of projections which are inserted into the corresponding mounting holes formed in the base plate and folded in a condition wherein the one end of the cylindrical body is retained in contact with the bottom surface of the base plate.
According to another aspect of the present invention, the base plate is formed with a plurality of mounting holes located at positions corresponding with the ice making cell casings, wherein the ice making cell casings each are in the form of a cup-shaped casing formed at its bottom with an annular flange which is coupled with the respective mounting holes of the base plate and welded to the base plate in a condition where the bottom of the cup-shaped casing coincides with the upper surface of the base, and wherein the cooling pipe is welded to the upper surface of the base plate in its entire length.
According to a further aspect of the present invention, the ice making cell casings are integrally formed with the bottom surface of the base plate, while the cooling pipe is mounted on the base plate along positions located above the cell casings and welded to the upper surface of the base plate. In this embodiment, it is preferable that the base plate is formed thereon with a support portion along positions located above the cell casings, and that the cooling pipe is positioned in engagement with the support portion of the base plate and welded to the base plate.